Printing-plate clamp



Oct. 27, 1936. w. s. WARNOCK PRINTING PLATE CLAMP 7 Filed June 3, 4955 Patented Oct. 27, 1936 UTED TES

PATENT OFFICE 6 Claims.

This invention relates particularly to means for securing a printingplate, or a printing-form, to a bed, and more particularly to such devices as make use of a foundation-plate provided with vertical perforations and so-called drop-in hooks which serve to secure the printing-plate to the foundation-plate.

The primary object is to provide a simplified construction of improved operation.

The invention is illustrated in a preferred embodiment in the accompanying drawing, in which- Fig. 1 is a broken vertical sectional View showing a portion of a printing-plate secured in position in accordance with the present invention; Fig. 2, a similar" view showing the clamp in released position; Fig. 3, a broken bottom plan View of the device shown in Fig. 1; Fig. 4, an elevational view of the improved clamping-device; and Fig. 5, a broken vertical sectional view showing a modification.

In the illustration shown in Figs. 1-4, A designates a foundation-plate provided with vertical perforations A which preferably converge downwardly and are provided at their lower ends with enlargements affording the shoulders A B, my improved plate-clamp; and C, a printing-plate supported on the foundation-plate A.

The device B comprises, in integral formation, a clamping-head i and a depending stem l a wedge-member 2 mounted in the stem; a spring 3 which normally tends to throw the clamp to a released position somewhat as shown in Fig. 2; and a wedge-actuating screw housed in the upper portion of the stem l The body of the clamp which comprises the clamping-head I and the stem l may be cast or formed from suitable metal. The stem of the body member is provided with a chamber 5 which opens through a lateral slot 5 at what may be termed the rear side of the member.

The wedge-member 2 is in the form of a short bar adapted to be substantially housed within the stem, this bar having its base-portion connected-with the stern by a transverse pivot 6, and the upper end of the bar being provided with a grooved beveled portion l adapted to coact with the adjusting screw 0.

The spring 3 preferably comprises a yielding socket-portion 3 which is received within the hollow socket 5 at the base of the stem, and a bent spring-arm which comprises an upwardly extending member 3* and a downwardly extending member 3 whose free extremity is adapted to bear against the wall of the perforation or cavity A just above the enlargement of the opening which forms the shoulder A The socket-portion 3 of the spring is in the form of a loop which has an extremity 3 upon which the lower end of the wedge-member 2 is seated and a shoulder 3 which engages the lower end of the slot 5 In assembling the parts, the wedge-member 2 is forced downwardly to bring its pivot-hole in registration with the transverse hole through the lower portion of the stem I and thus, the socket-portion 3 of the spring is placed under compression, which tends to throw the wedge-member 2 to the closed or inoperative position shown in Fig. 2.

Owing to the fact that the extremity of the member 3 of the spring bears against the lower portion of the wall of the perforation A, the tendency of the spring is to force the plate-clamp to the inoperative position shown in Fig. 2. In this position, however, the shoulder A is engaged by lugs l (Fig. 3) which are formed integrally with the lower end of the stem I This is a matter of convenience. in positioning the printing plate when the plate is surrounded by a number of the clamping devices. Also, the device is effectively held in the perforation in the foundation plate, even before the clamping operation is performed.

The screw 4 has threaded connection at 8 with the wall of the upper portion of the chamber 5. The screw has a rounded lower end portion 4 which engages the inclined groove 1. Also, the screw is provided with an angular socket 4 which registers with an axial perforation 9 which extends through the top wall of the chamber 5, that is, through the clamping head I.

In the modification shown in Fig. 5, the construction corresponds with the construction already described, except that the spring, designated i0, is a modified form. The other parts are designated by the same characters used in the' above description. In this modification, the spring has a socket-portion l0 which affords a yielding bearing for the base of the wedge-member 2; and it has an upwardly pointing springarm Ni which engages the wall of the perforation A at a medial point, that is, at a substantial distance above the shoulder A The form of spring illustrated in Figs. 1-4 is preferred because it tends to throw the plateclamp to the inoperative position shown in Fig. 2. When the screw 4 is turned downwardly, as by means of a key, or tool I I, the upper end-portion of the wedge-member is caused to engage the opposed wall of the perforation A and force the clamp to the clamping position shown in Fig. 1.

In both of the forms of spring illustrated, simplicity of formation and assembly is accomplished; and in both forms the socket-portion of the spring forms a spring-seat for the wedgemember 2, which tends to throw the wedge-member to the inoperative position.

The improved device is extremely simple, may be manufactured cheaply, and may be used with very great facility.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible in view of the prior art.

What I regard as new and desire to secure by Letters Patent is:

1. In combination with a foundation-plate provided with vertical apertures and having an upper surface adapted to support a printing-plate: a printing-plate clamp comprising a clampinghead and a stem depending therefrom adapted to extend into an aperture, a wedge-member pivotally connected wtih said stem, axial means in said stem for actuating said wedge-member, and a spring having a socket-portion mounted in the lower portion of said stem and affording a yielding bearing for the lower end of said wedge-member and having a spring-arm adapted to engage an opposed wall of the aperture.

2. Means as specified in claim 1, in which the arm of said spring is bent and has a depending free extremity adapted to engage the lower portion of the wall of said aperture.

3. Means as specified in claim 1, in which the foundation-plate is provided with shoulders near the lower ends of the apertures and the stem of the plate-clamp is provided with a lug adapted to engage such a shoulder.

4. In combination with a foundation-plate provided with vertical perforations having downwardly converging walls and enlargements at their lower ends affording shoulders: a printingplate clamp comprising a clamping head and a depending stem having its lower end-portion equipped with a lug for engaging the shoulder mentioned, a wedge-member pivotally mounted on the lower portion of said stem, an axial screw in the upper portion of said stem for actuating said wedge-member, and a spring carried by the lower portion of said stem and engaging the lower end of said wedge member and the lower portion of the wall of the perforation and serving normally to throw the printing-plate clamp to inoperative position.

5. A printing-plate clamping device comprising, in integral formation, a clamping-head and a stem depending therefrom provided with a chamber and with a lateral slot opening from said chamber, the lower portion of said stem being provided with a socket, a Wedge-member having its lower end-portion pivotally mounted in said chamber, an axial screw connected with said stem and actuating said wedge-member, and a spring having a looped socket-portion received in said socket and forming a yielding seat for the lower end of said wedge-member, said spring having an arm adapted to engage a wall of a perforation in a foundation-plate.

6. A device as specified in claim 5, in which the spring-arm of said spring is a bent member provided with a depending extremity which is adapted to engage the lower portion of the wall of said perforation.

WALLACE S. WARNOCK. 

